Chronic Lymphocytic Leukemia: Novel Therapeutic Targets Under Investigation

Abstract

CLL is the most prevalent adult leukemia in Western countries, characterized by the accumulation of monoclonal B lymphocytes. Over the past decade, the therapeutic landscape for CLL has undergone significant transformations, primarily due to the introduction of targeted small molecular therapies like BTK inhibitors and BCL-2 inhibitors, that have improved patient outcomes drastically. Despite significant advances, long-term disease management remains challenging for patients with double-refractory CLL, where responses with subsequent therapies are short-lived. Resistance to these therapies can arise through several mechanisms like kinase-altering BTK mutations, alterations in the BCL-2 pathway, and adaptations within the tumor microenvironment, necessitating the exploration of new therapeutic options. This review provides an in-depth overview of the promising novel treatment approaches under investigation in CLL, focusing on advanced cellular therapies (CAR T-cell therapy), T-cell engagers, new monoclonal antibodies, and various next-generation small molecule inhibitors including BTK degraders, PI3K inhibitors, MALT1 inhibitors, c-MYC inhibitors, CDK9 inhibitors, and agents targeting angiogenesis and DNA damage repair. In this review, we will discuss the novel therapeutic targets and agents as well as ongoing trials, emphasizing the potential of these treatments to overcome resistance and meet the unmet needs of patients, particularly those with double-refractory CLL.

Keywords: BTK degraders; CAR T-cell therapy; T-cell engagers; chronic lymphocytic leukemia; double-refractory CLL; novel targets; small molecule inhibitors.

Figure 1

Current treatment landscape and novel therapeutic targets in CLL. Current CLL treatment targets (Black): CAR T cells, CAR T + BTK inhibitors, BCL-2 inhibitors, monoclonal antibodies (mAbs), covalent and non-covalent BTK inhibitors. Novel targets in development (green): Cellular therapies, T-cell engagers, novel monoclonal antibodies, small molecule engagers.